1. Field of the Invention
This invention relates to a gas-liquid separation flow rate regulator in a sewage disposal tank, which separates air in sewage sucked through a suction pipe, suspended in the tank and connected to an air lift pump, from sewage at the upper end of the suction piper. This invention finely regulates the flow rate of sewage and returns a suitable amount of regulated sewage back to a treatment tank in a preceding stage.
2. Description of the Related Art
A conventional gas-liquid separation flow rate regulator of this kind has the construction shown in FIG. 6. Namely, a square regulation box A is disposed at the upper end of a suction pipe 3 suspended into a tank and the inside of this regulation box is divided into a primary inflow chamber 8 and a secondary inflow chamber 9 by a partition plate 7 having a V-shaped overflow portion 10 at the center of the upper edge thereof. A discharge port 3a of the suction pipe 3 is downwardly opened into the primary inflow chamber 8, and the lower end of a gate plate 11 capable of moving up and down is disposed so as to face the bottom surface of the primary inflow chamber 8. An escape port 4a bored through the bottom surface of the regulation box A is disposed so as to face the back side of the gate plate 11 and a return port 12 of regulated sewage is disposed in the secondary inflow chamber 9.
The operation of this regulator is as follows. A large quantity of sewage sucked by the air lift pump is discharged from the discharge port 3a of the suction pipe 3 into the primary inflow chamber 8, and sewage thus discharged is caused to flow out through a predetermined gap between the lower surface of the gate and the bottom surface of the regulation box A which is set in advance by the positioning of gate plate 11. After being first regulated in this way, sewage flow into the secondary in flow chamber through the overflow portion 10 is then regulated, and sent back to a treatment tank of a preceding stage through the return port 12. This type of construction is an typical of this kind of conventional gas-liquid separation flow rate regulators.
Since the conventional gas-liquid separation flow rate regulator A described above employs the rectangular box at its main body, each of the inside surfaces of the box is a flat wall. As a result, air-containing sewage rigorously discharged downward from the discharge port 3a of the suction pipe 3 impinges against the inside bottom wall surface of the primary inflow chamber 8 and causes the water level of the inflow chamber 8 to assume a vigorous uncontrolled flow state. Accordingly, gas-liquid separation cannot be accomplished in a satisfactory manner. When sewage passes through the overflow portion 10 in this uncontrolled flow state, it cannot be settled nor can it flow into the secondary inflow clamber 9 from the overflow portion 10 as expected. Accordingly, satisfactory water regulation is problematic and cannot be obtained in a suitable manner.